Airline and Plane's Manufacturer Point Fingers on the Cause of the 2001 Queens Air Crash

By MATTHEW L. WALD

Published: March 21, 2004

WASHINGTON, March 20—
In an unusual public spat, American Airlines and Airbus are blaming each other for the crash of Flight 587 in Queens in November 2001. The plane's vertical tail fell off shortly after takeoff from Kennedy International Airport on a flight to the Dominican Republic.

The dispute between the airline and the plane's manufacturer centers on whether the design of the control system or pilot training led to the crash, which killed all 260 aboard the plane and five people on the ground.

In briefs submitted to the National Transportation Safety Board earlier this month, the airline accused Airbus of suppressing information about previous control problems involving the plane model, an A-300, and similar planes. Those incidents, said American, indicated a design problem with the rudder that made it difficult to control at the speed the plane was flying.

In its briefs, however, Airbus contends that American improperly trained the pilot in the use of the rudder, and had been warned before the crash that its pilot training was wrong.

''They're certainly pointing fingers in each other's direction, and it's a 'not my fault' kind of thing,'' said one investigator in a high-level position at the agency, who asked not to be named because the five members of the board have not yet ruled in the case. The board had said it would take action in the spring, but recently delayed a decision until summer.

The briefs are public record, but are not yet posted on the board's Web site. When they were submitted, American took the unusual step of sending e-mail messages to reporters with its version of events; Airbus did the same a few hours later.

Investigators say the board will certainly cite both the design issue and pilot training as contributing to the crash, but it is not clear which they might say is more important. ''I would put it design first, training second, but you could argue over that,'' said one longtime investigator, who also asked not to be named because of the board's pending decision. ''The pilot did it,'' he said. But he added: ''He responded the way he was trained. He didn't do anything wrong.''

Since the accident, investigators from the National Transportation Safety Board and the Federal Aviation Administration and others have looked closely at previous incidents in which Airbus A-300-600's, the precise model involved, swung from side to side because of rudder movements by the pilots.

''This accident never should have happened and could have been prevented if Airbus had disclosed to American, the F.A.A. or the safety board what it knew about the propensity of the flight control system on the A-300-600 to allow hazardous rudder control inputs that could cause structural damage,'' American said in its brief.

American pointed out that an independent study, commissioned by the safety board, found that the plane had gone through a ''pilot-induced oscillation,'' or a back-and-forth motion that was created by actions of the pilot, but not intended. The pilot, encountering turbulence from a plane ahead, pushed a foot pedal to extend the rudder all the way in one direction, then the other, then switched again. As the tail of the plane moved sideways, it came under more pressure than it was designed to withstand and broke off.

But the author of the study, Ronald A. Hess of the University of California, said that the design of the rudder was conducive to such oscillations. One problem, he found, was that on the A-300, the amount of force needed to start moving the rudder was relatively high, and the total range of motion allowed at that speed was only a little over an inch, making it very difficult to apply any amount of rudder less than its full extension. In addition, rudder application does not move the plane instantly, and the delay might encourage a pilot to keep applying the rudder until the aircraft moved further than the pilot intended, according to Mr. Hess's analysis. The natural reaction would then be to apply the rudder in the opposite direction.

Complicating the problem, aeronautical engineers write specifications for each plane, stating that pilots should not use the rudder above a certain speed, called ''maneuvering speed.'' Pilots are taught that below that speed, they can use the rudder as needed; Flight 587 was moving below that speed. But unknown to most pilots, according to aviation authorities, the engineers intend a single application of the rudder, not a repeated, alternating application, which in the case of Flight 587 built up a swinging motion that broke the tail.

But Airbus said that the pilot of Flight 587 inappropriately worked the controls, and it added, in bold type, ''exactly as he was taught to do.'' Airbus contends that American put the pilot through a special training program for how to recover from in-flight ''upsets'' that included rudder use. The program, Airbus said, put pilots through a simulator that de-emphasized the effectiveness of other controls and thus encouraged rudder use.

The force required to move the pedals, and the pedal travel distances, met certification requirements, Airbus said, and the one that crashed had no mechanical flaws before the accident. In addition, it said, ''no adverse comments were received form the operators after more than 16 million flight hours.''

Technically the board's decision is not admissible in court, but it will probably play a role in dividing up damages from lawsuits resulting from the crash.